Tower packing



Nov. 5, 1963 D. H. MOELLER 3,109,876

TOWER PACKING Filed Oct. 6, 1960 14 E I I I E m 12 E 14 17 INVENTOR,De/rner {i M Aer United States Patent 3,109,876 TOWER PACKING m1 DelmarH. Moeller, Midland, Mich assignor to the Dow Chemical Company, Midland,Mich, a corporation of Delaware Filed Oct. 6, 1950, Ser. No. 61,!l 4Claims. (Cl. 261-112) This invention relates to sheet assembly andapparatus for the distribution of flowing liquid through a plurality ofthin films. More particularly, it relates to a method of assembling atower packing for extended surface elements for gas liquid contacts andthe product prepared thereby.

Many cooling towers, and towers for biological oxidation, employassemblies of sheets positioned generally in parallel relationship.Frequently, such sheets are prepared from plastics, such as polystyreneand polyethylene and are assembled into a generally rectangular group orbundle. A plurality of such bundles are placed within a tower to provideadditional surface to facilitate the contact of a flowing liquid filmwith air or other gas passing through the tower.

A typical sheet assembly which may be employed in the practice of theinvention is shown in US. Letters Patent No. 2,793,017. In the packingof a typical tower, bundles of parallel sheet elements are placed in thetower, the sheets maintained generally parallel and oriented in asubstantially vertical plane, as further bundles are added to completethe lower layer, the parallel relationship of the individual sheets inthe bundle assemblies is maintained. Similar layers of bundles arestacked vertically in matching relationship. This arrangement results ina cubic packing. By cubic packing is meant that the centers of the sheetbundles lie in planes vertically and horizontally at right angles toeach other and are disposed in relation to adjacent bundles as thecorners of a cube or right parallelepiped.

Bundles of sheets fabricated from plastic materials and particularly thethermoplastics, such as polystyrene, polyethylene, and polyvinylchloride, exhibit limited structural strength, and the depth of packingpermitted between support platforms in a tower is dependent on theinitial edgewise resistance of the individual rectangular bundles todeform along any one of the three principal axes. Generally, deformationof the bundles takes place along a horizontal axis parallel to thesheets forming a bundle. Failure of the bundle often occurs Where thereis a tendency for solids to build up on the tower packing in op eration.This action is particularly prevalent in biological oxidation processwherein a slime forms on the surface of the individual sheets frequentlycausing a relatively large increase in the load which must be supportedby the sheet bundles, particularly by the sheet bundles disposed towardthe lower portion of the tower.

It is an object of the invention to provide a method of stacking in atower generally rectangular bundles of generally parallel elements whichwould provide packing having improved resistance to deformation underload.

It is a further object to provide a method of packing such bundles whichwould result in a smaller side thrust load being applied to the towerWalls.

It is still a further object to provide a method of packing a tower withgenerally rectangular bundles of substantially parallel sheets or laminawhich would reduce the shear stress between adjacent sheets in saidbundle.

It is another object of the invention to provide a tower packingassembly of improved rigidity.

These objects, advantages, and other benefits may be obtained bypositioning in a tower, a packing comprising a plurality of generallyparallel-lamina, tower packing "ice bundles, said bundles arranged inlayers, said bundles being positioned in horizontal layers in a squarepattern; said bundles in each of said layers being arranged with thelamina of adjacent bundles substantially normal to each other; and saidlamina lying in a substantially vertical plane.

Other advantages and objects of the present invention will becomeapparent in the following description and specification taken inconnection with the accompanying drawing, wherein:

FIGURE 1 schematically represents a top view of one layer of bundlesemployed in a tower packing;

FiGURE 2 represents a top view of a layer arrangement wherein fractionalbundles are employed; and

FIGURE 3 schematically represents the arrangement of several layers ofbundles employed in a tower packing.

In FIGURE 1 there is schematically represented a top view of a layer oftower packing generally designated by the reference numeral 14)positioned within a tower 9 of rectangular cross section. The layer 10is made up of a plurality of bundles 12, each of said bundles 12comprising a plurality of adjacent sheets 14. The bundles 12 arearranged in such a manner that bundles adjacent to each other have theirsheets 14 substantially normal to a plane parallel to the sheets 14 ofall adjacent bundles.

FIGURE 2 illustrates a layer of tower packing generally indicated by thereference numeral 11. The layer 11 comprises a plurality of bundles -12centrally located and surrounded by half bundles 16 and quarter bundles17 disposed at the corners of the layer 11. Each of the bundles 12 andthe fractional bundles 16 and 17 is oriented with the sheets or lamina14 substantially normal to the sheets 14 in adjacent whole or fractionalbundles.

In FIGURE 3 there is a schematic, cutaway representation of a tower 9containing layers ll of bundles alternating with layers 11 of bundles.The layers designated 11. differ only from the layers 10 in the factthat half bundles 16 are positioned at the sides and quarter bundles 17at the corners. The half bundles l6 and quarter bundles 17 cause thecenters of the bundles 12 to be disposed generally colinear with thecorners of the upper and lower adjacent bundles.

In constructing a packed tower according to the method of the invention,bundles 12 of parallel elements 14 may be placed into the towerindividually or in groups of two or more alternating the configurationin such a way that the ends of the elements 14 of a bundle support thesides of the two adjacent bundles from deformation in their physicallyweak direction. Thus, the initial layer of bundles provides a relativelyrigid unit that has a substantially smaller tendency to deform than if anormal packing method were used wherein the sheets 14 in the bundles 12are substantially parallel to each other.

The second layer is readily prepared by employing half bundles 15 at theends of the full size bundles 12 employing sheet or lamina orientationsimilar to that of the first layer. Bundle 12 centers are displaced outof vertical alignment with the bundle centers of layer 10 and thus,positioned with the geometric centers over the center of one edge of thebundles in the layer below by employing half bundles at ends of rows.

Thus, half bundles 16 may be employed to offset the centers of thebundles 12 in one direction or quarter and half bundles l7 and 16 may beemployed if the geometric center of the bundle is to be positioned overa point substantially common to four bundles in the lower layer.

The gain in physical strength employing the method of the invention issignificant and is dependent upon the particular physicalcharacteristics of the individual sheets 14 of the bundle elements 12;thus, in general the strength is dependent on, and proportional to, thestillness of the J9 bundle elements in a direction generally parallel tothe surface of the elements 14.

Towers of circular and other nonrectangular shapes may be packed inaccordance with the invention by trimming the bundles positionedadjacent the tower walls or wall not in rectangular arrangement.

While the invention has been described with reference to particularembodiments, it is to be understood that more modifications thereof maybe made without departing from its scope, particularly as defined in thehereto appended claims.

That which is claimed is:

1. In a method of packing a tower for the contact of a liquid with a gasemploying as packing material a plurality of horizontal layers ofgenerally rectangular tower packing bundles, said bundles beingself-supporting, each of said layers being composed of a plurality ofsaid bundles; said bundles consisting essentially of a plurality ofgenerally parallel self-supporting thermoplastic lamina; the

improvement which comprises: arranging said bundles in each of saidlayers in a square pattern, further arranging said bundles in each ofsaid layers with the lamina of adjacent bundles substantially normal toeach other and with said lamina lying in substantially vertical planes,and locating the centers of vertically adjacent bundles in a displacedposition from a vertical line passing through said centers.

2. A method in accordance with claim '1, wherein the centers ofvertically adjacent bundles are positioned vertically adjacent to thecorners of a vertically adjacen bundle in an adjacent layer.

3. In a tower for the contact of a liquid with a gas employing as apacking material a plurality of horizontal layers of tower packingbundles, said bundles being selfsupporting, each of said layers beingcomposed of a plurality of said bundles, said bundles consistingessentially of a plurality of generally parallel thermoplastic lamina,said lamina lying in a substantially vertical plane, the improvementwhich comprises: the parallel lamina of each bundle being disposedsubstantially normal to the lamina of adg'acent bundles, verticallyadjacent bundles are displaced from a vertical line passing through thecenters of the vertically adjacent'bundles.

4. A tower in accordance with claim 3, wherein the centers of verticallyadjacent bundles are disposed vertically adjacent to the corners of avertically adjacent bundle in an adjacent layer.

References Cited in the file of this patent UNITED STATES PATENTS855,448 Doherty June 4, 1907 2,080,713 Hayes May 18, 1937 2,376,341 Burket al. May22, 1945 2,571,958 Slaughter et al. Oct. 16, 1951 2,656,168Ayres Oct. 20, 1953 2,793,017 Lake May 21, 1957 2,977,103 Smith et a1Mar. 28, 1961 FOREIGN PATENTS 743,793 Great Britain Jan. 25, 1956

3. IN A TOWER FOR THE CONTACT OF A LIQUID WITH A GAS EMPLOYING AS APACKING MATERIAL A PLURALITY OF HORIZONTAL LAYERS OF TOWER PACKINGBUNDLES, SAID BUNDLES BEING SELFSUPPORTING, EACH OF SAID LAYERS BEINGCOMPOSED OF A PLURALITY OF SAID BUNDLES, SAID BUNDLES CONSISTINGESSENTIALLY OF A PLURALITY OF GENERALLY PARALLEL THERMOPLASTIC LAMINA,SAID LAMINA LYING IN A SUBSTANTIALLY VERTICAL PLANE, THE IMPROVEMENTWHICH COMPRISES: THE PARALLEL LAMINO OF EACH BUNDLE BEING DISPOSEDSUBSTANTIALLY NORMAL TO THE LAMINA OF ADJACENT BUNDLES, VERTICALLYADJACENT BUNDLES ARE DISPLACED FROM A VERTICAL LINE PASSING THROUGH THECENTERS OF THE VERTICALLY ADJACENT BUNDLES.